Package org.apache.wayang.basic.function

Class ProjectionDescriptor<Input,Output>

java.lang.Object

org.apache.wayang.core.function.FunctionDescriptor

org.apache.wayang.core.function.TransformationDescriptor<Input,Output>

org.apache.wayang.basic.function.ProjectionDescriptor<Input,Output>

All Implemented Interfaces:

Serializable

public class ProjectionDescriptor<Input,Output>
extends TransformationDescriptor<Input,Output>

This descriptor pertains to projections. It takes field names of the input type to describe the projection.

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.wayang.core.function.FunctionDescriptor

FunctionDescriptor.ExtendedSerializableBinaryOperator<Type>, FunctionDescriptor.ExtendedSerializableConsumer<T>, FunctionDescriptor.ExtendedSerializableFunction<Input,Output>, FunctionDescriptor.ExtendedSerializablePredicate<T>, FunctionDescriptor.SerializableBiFunction<Input0,Input1,Output>, FunctionDescriptor.SerializableBinaryOperator<Type>, FunctionDescriptor.SerializableConsumer<T>, FunctionDescriptor.SerializableFunction<Input,Output>, FunctionDescriptor.SerializableIntUnaryOperator, FunctionDescriptor.SerializableLongUnaryOperator, FunctionDescriptor.SerializablePredicate<T>, FunctionDescriptor.SerializableToDoubleBiFunction<T,U>, FunctionDescriptor.SerializableToLongBiFunction<T,U>, FunctionDescriptor.SerializableToLongFunction<T>

Field Summary

Fields inherited from class org.apache.wayang.core.function.TransformationDescriptor

inputType, outputType

Constructor Summary

Constructors

Constructor	Description
ProjectionDescriptor(Class<Input> inputTypeClass, Class<Output> outputTypeClass, String... fieldNames)	Creates a new instance.
ProjectionDescriptor(FunctionDescriptor.SerializableFunction<Input,Output> javaImplementation, List<String> fieldNames, BasicDataUnitType<Input> inputType, BasicDataUnitType<Output> outputType)	Basic constructor.
ProjectionDescriptor(BasicDataUnitType<Input> inputType, BasicDataUnitType<Output> outputType, String... fieldNames)	Creates a new instance.

Method Summary

Modifier and Type	Method	Description
static ProjectionDescriptor<Record,Record>	createForRecords(RecordType inputType, String... fieldNames)	Creates a new instance that specifically projects Records.
List<String>	getFieldNames()

Methods inherited from class org.apache.wayang.core.function.TransformationDescriptor

getInputType, getJavaImplementation, getOutputType, getSqlImplementation, toString, unchecked, withSqlImplementation

Methods inherited from class org.apache.wayang.core.function.FunctionDescriptor

getLoadProfileEstimator, getSelectivity, setLoadEstimators, setLoadProfileEstimator

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

ProjectionDescriptor

public ProjectionDescriptor(Class<Input> inputTypeClass,
 Class<Output> outputTypeClass,
 String... fieldNames)

Creates a new instance.

Parameters:

inputTypeClass - input type

outputTypeClass - output type

fieldNames - names of the fields to be projected

ProjectionDescriptor

public ProjectionDescriptor(BasicDataUnitType<Input> inputType,
 BasicDataUnitType<Output> outputType,
 String... fieldNames)

Creates a new instance.

Parameters:

inputType - input type

outputType - output type

fieldNames - names of the fields to be projected

ProjectionDescriptor

public ProjectionDescriptor(FunctionDescriptor.SerializableFunction<Input,Output> javaImplementation,
 List<String> fieldNames,
 BasicDataUnitType<Input> inputType,
 BasicDataUnitType<Output> outputType)

Basic constructor.

Parameters:

javaImplementation - Java-based implementation of the projection

fieldNames - names of the fields to be projected

inputType - input BasicDataUnitType

outputType - output BasicDataUnitType

Method Details

createForRecords

public static ProjectionDescriptor<Record,Record> createForRecords(RecordType inputType,
 String... fieldNames)

Creates a new instance that specifically projects Records.

Parameters:

inputType - input RecordType

fieldNames - names of fields to be projected

Returns:

the new instance

getFieldNames

public List<String> getFieldNames()